Rock dust product for managing two-spotted spider mites (Acari: Tetranychidae) on grapevines (Vitaceae)

Abstract Growing environmental concerns and the rise of pesticide resistance have prompted a critical need to develop alternatives to synthetic chemical insecticides. In this context, mineral-based products offer a promising solution for integrated pest management. This study examines the potential of a granite dust product as a control agent for two-spotted spider mites, Tetranychus urticae Koch (Acariformes: Tetranychidae), on grapevines, Vitis spp. (Vitaceae). Using two-choice repellency, repulsiveness, and no-choice bioassays involving substrate, foliar, and combined applications, the dust was found to effectively deter mites from moving from control leaves to treated leaves in repulsiveness tests; however, in repellency tests, some but not all mites moved from treated leaves to control leaves. Significantly higher mite mortality was observed across all dust treatments in both bioassays than in control treatments, suggesting that contact exposure to the dust and potentially the accumulation of silica in cell walls in plants treated with rock dust as a substrate amendment could render the cell walls resistant to piercing by spider mite mouthparts. The findings improve the understanding of this product’s potential for pest management.